Crate bouncycastle_sha2 

Implements SHA2 as per NIST FIPS 180-4.

Examples

Hash

Hash functionality is accessed via the bouncycastle_core::traits::Hash trait, which is implemented by SHA224, SHA256, SHA384 and SHA512.

The simplest usage is via the static functions.

use bouncycastle_core::traits::Hash;
use bouncycastle_sha2 as sha2;

let data: &[u8] = b"Hello, world!";
let output: Vec<u8> = sha2::SHA256::new().hash(data);

More advanced usage will require creating a SHA3 or SHAKE object to hold state between successive calls, for example if input is received in chunks and not all available at the same time:

use bouncycastle_sha2 as sha2;
use bouncycastle_core::traits::Hash;

let data: &[u8] = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F
                    \x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F
                    \x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F
                    \x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F";
let mut sha2 = sha2::SHA256::new();

for chunk in data.chunks(16) {
    sha2.do_update(chunk);
}

let output: Vec<u8> = sha2.do_final();

Suspending and resuming execution

When hashing a large message, it can be advantageous to be able to suspend the operation to a cache and resume it later; for example if waiting for the message to stream over a slow network connection.

For this reason, all SHA2 algorithms impl Suspendable.

use bouncycastle_sha2 as sha2;
use bouncycastle_core::traits::{Hash, Suspendable};

let msg_part1 = b"The quick brown fox";
let msg_part2 = b" jumped over the lazy dog";

let mut sha2 = sha2::SHA256::new();
sha2.do_update(msg_part1);

// suspend the in-progress extract while "waiting" for the second part of the message.
let serialized_state = sha2.suspend();

// ...
// do other things in the meantime
// ...

// ... later, possibly on another host: resume from the serialized state.
let mut sha2_resumed = sha2::SHA256::from_suspended(serialized_state).unwrap();
sha2_resumed.do_update(msg_part2);
let h: Vec<u8> = sha2_resumed.do_final();

Structs

SHA224Params

The parameters for SHA224.

SHA256Internal

Internal struct for SHA256. This uses a private bound so that you cannot instantiate it directly and have to use the provided and NIST-approved parameters.

SHA256Params

The parameters for SHA256.

SHA384Params

The parameters for SHA384.

SHA512Internal

Internal struct for SHA512. This uses a private bound so that you cannot instantiate it directly and have to use the provided and NIST-approved parameters.

SHA512Params

The parameters for SHA512.

Constants

SHA224_NAME

SHA256_NAME

SHA384_NAME

SHA512_NAME

SUSPENDED_SHA256_STATE_LEN

Length in bytes of the serialized state of SHA224 and SHA256.

SUSPENDED_SHA512_STATE_LEN

Length in bytes of the serialized state of SHA384 and SHA512.

Type Aliases

SHA224

Public type for SHA224.

SHA256

Public type for SHA256.

SHA384

Public type for SHA384.

SHA512

Public type for SHA512.